By Ryan Naraine
December 5, 2006
Microsoft on Dec. 5 warned that an unpatched vulnerability in its Word
software program is being used in targeted, zero-day attacks.
A security advisory from the Redmond, Wash., company said the flaw can
be exploited if a user simply opens a rigged Word document.
Affected software versions include Microsoft Word 2000, Microsoft Word
2002, Microsoft Office Word 2003, Microsoft Word Viewer 2003, Microsoft
Word 2004 for Mac and Microsoft Word 2004 v. X for Mac. The Microsoft
Works 2004, 2005 and 2006 suites are also affected because they include
There are no pre-patch workarounds available. Microsoft suggests that
users "not open or save Word files," even from trusted sources. "As a
best practice, users should always exercise extreme caution when opening
unsolicited attachments from both known and unknown sources," the
Users who have installed and are using the Office Document Open
Confirmation Tool for Office 2000 will be prompted with Open, Save or
Cancel before a file is opened. This offers a minor warning mechanism
for Word users.
The high-risk alert comes exactly one week before the company's
scheduled December Patch Tuesday, but there is no word yet from
Microsoft on the timing of its fix for Word.
The MSRC (Microsoft Security Response Center) has activated its incident
response process, which includes coordination with anti-virus and
security vendors and the creation of a software update. According to the
advisory, Microsoft may consider an out-of-cycle patch if necessary.
At press time on Dec. 5, there were no detection signatures available
from anti-virus vendors.
This is the second major Microsoft Word zero-day attack this year. In
May 2006, a sophisticated attack originating from China and Taiwan was
detected using a Trojan dropper and a backdoor with rootkit features to
mask itself from anti-virus scanners.
There have been several zero-day flawsand targeted attacksfound in
Microsoft Office applications, including Excel, PowerPoint and
Publisher. Many security experts said they believe corporate espionage
is the main motive behind the attacks.
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